This article looks back over two decades of work pioneered by Todd LaPorte and colleagues, under the banner of High Reliability Theory (HRT). The article revisits the American roots of the Berkeley-based group and comments on its early and decisive fieldwork choices. It revisits some of the elements that emerged through the controversy around findings and implications of HRT. It discusses the legacy of HRT and the ethnographical impetus given to "normal operations" studies. The use of ethnographic and sociological methodologies gave new vitality to the study of high-risks organizations.